Compressor and kit repairing and inflating inflatable articles

ABSTRACT

A non-lubricated, rotary vane compressor of maximum 10-70 litres/minute capacity, and having a pump body defining a cavity; a rotor having a cylindrical body housed in the cavity; a number of vanes; an inlet and outlet connected to the cavity; and a non-return valve fitted to the outlet.

TECHNICAL FIELD

The present invention relates to an improved, direct-current or DC vane compressor for a kit for repairing and inflating inflatable articles, in particular tyres, and to a kit comprising such a compressor. The compressor also applies non-limitingly to 12V systems used for a wide range of two- and/or four-wheel vehicle applications, as opposed to hobby applications, and/or to applications that call for a silent-operating, DC compressor with a wide 1-10 bar pressure range and low 7-30 ampere absorption.

A tyre repair and inflation kit is preferably compact, for easy handling by any user, and silent-operating.

High delivery pressure enables fast inflation of automobile, motorcycle and even commercial vehicle tyres, but should not increase the size of the kit, for the reason given above, or increase electric current absorption, to avoid overloading the vehicle's electric system, which could discharge the battery and at least temporarily affect the reliability of on-vehicle equipment. Moreover, vehicle electric systems are low-current, which means equipment powered by them must also be capable of efficient, low-current operation.

A need is felt for compressors of simple design, with a small number of component parts, designed to meet increasing demand in the automobile market for low-cost technology, and which are therefore cheap to produce. A miniaturized compressed-air vane compressor, of improved performance as compared with ordinary alternating compressors and as yet not employed in automobiles, could have big advantages in terms of performance, silent operation, and scope.

The most obvious hurdles in miniaturizing such a low-cost compressor, which would have to operate with no lubrication, are substantially:

1) the materials to use, which must be low-friction, with a sufficient temperature gradient;

2) optimum sealing between the assembled parts, in particular between the rotor and stator, between the vanes and rotor, and therefore between the vanes and stator;

3) sufficiently good efficiency of the air intake and pressurized air to reduce “parasitic air” circulation inside the compressor.

The above requirements apply to, and may successfully become characteristic of kits for repairing and inflating inflatable articles, but also apply to other applications as well.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide a vane compressor designed to at least partly meet the above requirements.

According to the present invention, there is provided a vane compressor as claimed in claim 1.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred, non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:

FIG. 1 shows a view in perspective of a kit which may be fitted with a compressor in accordance with the present invention;

FIG. 2 shows an axial section of a vane compressor in accordance with the present invention;

FIG. 3 shows a section along line in FIG. 2;

FIG. 4 shows a longitudinal section of a component part of the FIG. 2 compressor;

FIG. 5 shows a section along line V-V in FIG. 4;

FIG. 6 shows a section along line VI-VI in FIG. 4;

FIG. 7 shows performance graphs of a compressor in accordance with the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Number 1 in FIG. 1 indicates as a whole a kit for repairing and inflating inflatable articles, and which is purely a non-limiting example of one application of the present invention. Kit 1 comprises a casing 2; a compressor assembly (described in detail below) housed in casing 2; and a canister assembly 3 connected releasably to the compressor assembly, e.g. as described and illustrated in International Patent WO-A1-2008001179 filed by the present Applicant.

More specifically, casing 2 comprises a substantially parallelepiped-shaped portion 4 for housing the compressor assembly; and a projecting portion 5 projecting from the front of portion 4 and defining a seat for at least partly housing canister assembly 3.

Canister assembly 3 contains a sealing fluid for repairing tyre punctures, and comprises a bottle 6 inverted in use; and a hose 7 connected to bottle 6 to feed the sealing fluid into the tyre.

Kit 1 also comprises a second hose 8 connected directly to the compressor assembly to inflate the tyre without injecting sealing fluid; and control means for selecting a repair mode, in which hose 7 and bottle 6 are connected to the compressor assembly, and an inflation mode, in which hose 8 is connected to the compressor assembly. The control means comprise, for example, a valve 12 switched by a knob 9 on casing 2, and having two outlets connected to canister assembly 3 and hose 8 respectively.

Kit 1 also comprises a power plug for powering a DC, i.e. direct-current, electric motor (not shown) of the compressor assembly from a vehicle electric system; and a switch 11 for turning the compressor assembly on.

According to the present invention, the compressor assembly comprises a rotary vane compressor 13 for producing compressed air for injection into the tyre, either via bottle 6 and hose 7 to make repairs, or via hose 8 to simply inflate the tyre.

More specifically, compressor 13 comprises a cylindrical pump body 14 defining a cavity 15; a rotor 16 housed in cavity 15; and an input shaft 17, of axis A, powered by the electric motor and connected to rotor 16.

Pump body 14 comprises a central block 18 defining cavity 15; and two flanges 19, 20 fixed to opposite sides of central block 18. Flanges 19, 20 are positioned angularly with respect to block 18 by a number of pins P; and respective sealing rings G are inserted to seal cavity 15.

Input shaft 17 has a projecting portion 21 projecting from flange 19 and connected to rotor 16 at least to rotate integrally with rotor 16. On the longitudinally opposite side of rotor 16 to projecting portion 21, input shaft 17 has a pin 23 supported radially on flange 20 by a bearing 24. Similarly, projecting portion 21 is supported radially on flange 19 by a bearing 25; and rotor 16, projecting portion 21, and pin 23 are preferably formed in one piece.

As shown in FIG. 3, compressor 13 defines an inlet 25 and an outlet 26 connected fluidically to cavity 15, and through which compressed air generated by rotation of the rotor flows. Accordingly, compressor 13 comprises a number of, e.g. four, vanes 27 housed slidably inside respective seats 28 equally spaced angularly and defined by rotor 16. In the non-limiting embodiment shown, seats 28 are preferably located along chord portions of the cross section of rotor 16, as opposed to radially. For example, seats 28 extend beyond the geometric centre of the cross section of rotor 16 with respect to the direction defined by a radius parallel to the sliding direction of vane 27 inside respective seat 28.

According to the present invention, air intake is assisted by the inlet combining a through a hole 29, and a slot 30 which communicates with and is tangentially larger than hole 29. More specifically, slot 30 is shallower than the thickness of flange 20.

Preferably, the size of slot 30, the location of outlet 26, and the angular distance between each two consecutive vanes 27 are such that no angular position of the rotor connects slot 30 fluidically to outlet 26.

That is, whatever the angular position of rotor 16, there is always at least one vane 27 interposed between inlet 25 and outlet 26. As shown in FIG. 3, preferably one or two vanes 27 are interposed between inlet 25 and outlet 26.

FIG. 4 shows a non-return valve 31 located in series between cavity 15 and outlet 26, and which comprises an annular insert 32 screwed inside a radial hole 33 in central block 18; a tubular body 34 with a threaded stem 35 screwed inside radial hole 33 to rest against annular insert 32; and a movable disk D inside a seat 36 defined between annular insert 32 and threaded stem 35.

More specifically (FIG. 4), annular insert 32 comprises a threaded flange 37 which engages radial hole 33; and a tubular portion 38 projecting axially from threaded flange 37. Threaded stem 35 defines a contoured seat S for housing the whole of tubular portion 38. According to the present invention, the contoured seat has a number of conduits 39 connected fluidically to outlet 26 and to a passage 40 in annular insert 32. Preferably, outlet 26 is defined by a preferably cylindrical hole with an axis B; and conduits 39 are straight, and are so located and of such a radius that the geometric surfaces defined by their respective lateral walls interfere with the geometric surface defined by the lateral wall of outlet 26, thus forming a number of windows 41 connecting outlet 26 to conduits 39.

Contoured seat S of tubular portion 38 is deeper, along axis B, than the height of tubular portion 38, so that seat 36 of movable disk D is defined between a top face 42 of contoured seat S and an end face 43 of tubular portion 38. Moreover, tubular portion 38 is smaller in diameter than the largest circle tangent to all of conduits 39, so that, when disk D is raised, outlet 26 is connected fluidically to cavity 15.

In a preferred embodiment of the present invention, at least pump body 14 and vanes 27 are made of highly wear-resistant, low-friction, non-metal material that can be pressed and/or machined easily, such as carbon-graphite. Generally speaking, other pressable materials of a lower density than metal materials may also be used for non-return valve 31.

By way of a non-limiting example of the application described, FIG. 7 shows the flow and energy consumption of a compressor, in accordance with the present invention, featuring a 30 mm diameter cavity 15, a 23 mm diameter rotor 16, and four vanes. More generally speaking, cavity 15 is less than 50 mm and preferably less than 40 mm in diameter.

As can be seen, consumption is low with respect to flow, and the compressor is compact in size.

High flow is also and substantially due to leakage being minimized by the design of non-return valve 31 and the angular position of slot 30 with respect to outlet 26. Slot 30, conveniently located according to the work point selected according to rotor rotation speed, compressor size and rotor-stator ratio, also improves air intake and the fill coefficient of the variable-volume chambers of compressor 13.

Clearly, changes may be made to the compressor as described and illustrated herein without, however, departing from the scope defined in the accompanying Claims.

For example, the number of vanes 27 may range from a minimum of two to a maximum of six.

Compressor 13 is preferably non-lubricated, i.e. operates dry or with a small amount of lubrication applied during manufacture. In other words, compressor has no lubrication circuit, and draws untreated outside air. 

1. A non-lubricated, rotary vane compressor (13) of maximum 10-70 litres/minute capacity, and comprising a pump body (14) defining a cavity (15); a rotor (16) having a cylindrical body housed in said cavity (15); a number of vanes (27); and an inlet (25) and outlet (26) connected to said cavity (15); the compressor being characterized by a non-return valve (31) fitted to said outlet (26).
 2. A compressor as claimed in claim 1, characterized by comprising a block (18) defining said cavity (15); and a first and second flange (19, 20) fixed to opposite sides of said block (18); and wherein, of said block (18), said first and second flange (19, 20), said rotor (16), and said number of vanes (27), at least three are made of non-friction, non-metal material.
 3. A compressor as claimed in claim 2, characterized in that said non-metal material can be pressed and machined.
 4. A compressor as claimed in claim 1, characterized in that said inlet (25), said outlet (26), and said vanes (27) are so configured that at least one vane (27) is interposed angularly between said inlet (25) and said outlet (26) for each position of said rotor (16).
 5. A compressor as claimed in claim 4, characterized in that the ratio between the diameter of said cylindrical body and the maximum dimension of said cavity (15) in a direction perpendicular to the axis of rotation of said rotor (16) ranges between 0.6 and 0.9.
 6. A compressor as claimed in claim 4, characterized in that the maximum diameter of said cavity (15) is 50 mm.
 7. A compressor assembly comprising a direct-current motor with a maximum consumption of 5-25 amperes.
 8. A kit for repairing and inflating inflatable articles, and comprising a compressor or compressor assembly as claimed in claim
 1. 